Pipe joint and manufacturing method of pipe joint

Patent metadata

Field	Value
Publication number	US-2023392737-A1
Application number	US-202318453690-A
Country	US
Kind code	A1
Filing date	Aug 22, 2023
Priority date	Feb 26, 2021
Publication date	Dec 7, 2023
Grant date	—

Abstract

Provided is a pipe joint including a cylindrical hollow, wherein the wall thickness of a part having the largest wall thickness of the pipe joint is 2 to 7 mm, the ratio of the length of the hollow in the axial direction (L) to the diameter of the hollow (D), (L/D), is 5 or less, the pipe joint contains a copolymer containing tetrafluoroethylene unit and a fluoro(alkyl vinyl ether) unit, the content of the fluoro(alkyl vinyl ether) unit of the copolymer is 2.8 to 6.0% by mass with respect to the whole of the monomer units, the melt flow rate at 372° C. of the copolymer is 4.0 g/10 min or higher and lower than 11.0 g/10 min, and the number of functional groups of the copolymer is 50 or less.

First claim

1 . A pipe joint comprising a cylindrical hollow, wherein
a wall thickness of a part having the largest wall thickness of the pipe joint is 2 to 7 mm, a ratio of a length of the hollow in an axial direction (L) to a diameter of the hollow (D), (L/D), is 5 or less, the pipe joint comprises a copolymer comprising tetrafluoroethylene unit and a fluoro(alkyl vinyl ether) unit, a content of the fluoro(alkyl vinyl ether) unit of the copolymer is 2.8 to 6.0% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of the copolymer is 4.0 g/10 min or higher and lower than 11.0 g/10 min, and the total number of —CF═CF 2 , —CF 2 H, —COF, —COOH, —COOCH 3 , —CONH 2 and —CH 2 OH of the copolymer is 50 or less.

2 . The pipe joint according to claim 1 , wherein the length of the hollow in the axial direction (L) is 20 mm or larger.

3 . The pipe joint according to claim 1 , wherein the fluoro(alkyl vinyl ether) unit of the copolymer is perfluoro(propyl vinyl ether) unit.

4 . The pipe joint according to claim 1 , wherein the content of the fluoro(alkyl vinyl ether) unit of the copolymer is 3.5 to 5.5% by mass with respect to the whole of the monomer units.

5 . The pipe joint according to claim 1 , wherein the melt flow rate at 372° C. of the copolymer is 5.0 to 9.0 g/10 min.

6 . The pipe joint according to claim 1 , wherein the melting point of the copolymer is 295 to 315° C.

7 . The pipe joint according to claim 1 , wherein the pipe joint is an injection molded article.

8 . A method for producing a pipe joint comprising:
inserting a cylindrical core material into a cavity of a mold, filling the cavity of the mold with a molten copolymer from an injection molding machine, cooling the molten copolymer to solidify, extracting the core material along an axial direction of the pipe joint, and taking the pipe joint out from the mold, wherein a ratio of a length of the hollow of the pipe joint formed by extracting the core material in the axial direction (L) to a diameter of the hollow (D), (L/D), is 5 or less, and a wall thickness of a part having the largest wall thickness of the pipe joint is 2 to 7 mm.

9 . The production method according to claim 8 , wherein a length of the core material is identical to the length of the hollow of the pipe joint in the axial direction (L).

Assignees

• Daikin Ind Ltd

Inventors

• Tsuda Hayato
• Isaka Tadaharu
• ZENKE Yumi
• Yamamoto Yukari
• Yamaguchi Yasuyuki
• Hamada Hiroyuki

Classifications

• F16L41/021 Primary

  T- or cross-pieces (F16L41/025, F16L41/026, F16L41/028 take precedence) · CPC title

• B29C45/14065

  Positioning or centering articles in the mould · CPC title

• B29C45/261 Primary

  having tubular mould cavities · CPC title

• B29C45/7207

  of the moulded articles · CPC title

• B29D23/001

  Pipes; Pipe joints (pleated hoses B29D23/18) · CPC title